import { Observable } from 'rxjs';
export interface IOptions {
    /**
     * Period of the interval to run the source$
     */
    interval: number;
    /**
     * How many attempts on error, before throwing definitely to polling subscriber
     */
    attempts?: number;
    /**
     * Strategy taken on source$ errors, with attempts to recover.
     *
     * 'exponential' will retry waiting an increasing exponential time between attempts.
     * You can pass the unit amount, which will be multiplied to the exponential factor.
     *
     * 'random' will retry waiting a random time between attempts. You can pass the range of randomness.
     *
     * 'consecutive' will retry waiting a constant time between attempts. You can
     * pass the constant, otherwise the polling interval will be used.
     */
    backoffStrategy?: 'exponential' | 'random' | 'consecutive';
    /**
     * Exponential delay factors (2, 4, 16, 32...) will be multiplied to the unit
     * to get final amount if 'exponential' strategy is used.
     */
    exponentialUnit?: number;
    /**
     * Range of milli-seconds to pick a random delay between error retries if 'random'
     * strategy is used.
     */
    randomRange?: [number, number] | undefined;
    /**
     * Constant time to delay error retries if 'consecutive' strategy is used
     */
    constantTime?: number;
    /**
     * Flag to enable background polling, ie polling even when the browser is inactive.
     */
    backgroundPolling?: boolean;
}
/**
 * Run a polling stream for the source$
 * @param request$ Source Observable which will be ran every interval
 * @param userOptions Polling options
 */
export declare function polling<T>(request$: Observable<T>, userOptions: IOptions): Observable<T>;